Exploring the bioactive potential of brewers spent grain ohmic extracts

Valorizing brewery industry waste in nanocellulose cryogel-PEG composites for cold chain packaging

Global concerns about food and energy waste call for new sustainable solutions. Phase changing materials (PCM) are promising thermal storage and management materials which have potential to mitigate food waste, yet they often suffer from leakage and non-shape stability. Here, a green shape-stabilized polyethylene glycol 300 (PEG) nanocellulose-based composite was developed using readily available and cost-effective side streams from the brewery industry. Two different routes were examined for the incorporation of PEG into the cellulose nanofiber (CNF) cryogel including adding different dry mass ratios of PEG in the sol stage, with or without physical crosslinking, or adding the PEG after CNF gelation. FTIR and TGA analysis revealed the improved thermal stability of PEG after incorporation into the CNF cryogel. The PEG/CNF composite produced by adding PEG in the gel stage outperformed the other material formulations by demonstrating the highest enthalpy value (93.2 J/g) and the best mechanical properties (Young's modulus of 140 kPa). The package containing the PEG/CNF composite could maintain the meat temperature below 0 °C around 4 times longer than the control package when the cold system was interrupted. Furthermore, the PEG/CNF composite showed a positive effect on the color and drip loss values of frozen meat.

Assessing the Potential of Brewer's Spent Grain to Enhance Cookie Physicochemical and Nutritional Profiles

Brewers' spent grain (BSG), the major by-product of the brewery industry, has high nutritional value, making it suitable for upcycling into products such as healthy, and sustainable cookies. Nonetheless, the incorporation of BSG in cookies can impact their quality, given the increased fiber and protein content. This work explored the effect of replacing wheat flour with BSG at 50% and 75% in cookie formulations, focusing on physical, chemical, and sensory properties. The dietary fiber, lipid, and protein content of cookies improved considerably with the highest incorporation of BSG, increasing from 6.37% to 15.54%, 9.95% to 13.06%, and 9.59% to 12.29%, respectively. Conversely, moisture and water activity decreased from 11.03% to 3.37% and 0.742 to 0.506, respectively, forecasting a lower risk of microbial contamination and increased shelf-life. The incorporation of BSG in cookies resulted in decreased brightness and increased hardness, from 40 N to 97 N. Moreover, colorimetric shifts among the control cookies and the two BSG-rich formulations could be easily identified by an untrained observer. Sensory evaluation showed that cookies with 50% BSG retained acceptable sensory characteristics, suggesting potential for further development. Overall, BSG enhances the nutritional profile of cookies with no excessive detrimental impact on sensory features.

Applying Subcritical Water Extraction to Obtain Bioactive Compounds and Cellulose Fibers from Brewer Spent Grains

Of the three types of waste generated in beer processing, brewer's spent grain (BSG) is the most abundant and has a high potential for valorization. In this work, defatted BSG (DB) was subjected to an extraction process with subcritical water at different temperatures to obtain extracts rich in phenols and the cellulosic fractions, which were also purified by using hydrogen peroxide (H2O2). The results showed that the dry extracts obtained at 170 °C were richer in phenolics (24 mg Gallic Acid Equivalent (GAE) g-1 DB), but with lower antioxidant capacity (71 mg DB·mg-1 2,2-diphenyl-1-pikryl-hydrazyl). This extract also showed the highest antibacterial potential against L. innocua (80 mg·mL-1) and E. coli (140 mg·mL-1) than those obtained at lower temperatures. The purification of cellulose from the treated residues, using hydrogen peroxide, revealed that DB is a limited source of cellulose material since the bleached fractions showed low yields (20-25%) and low cellulose purity (42-71%), even after four bleaching cycles (1 h) at pH 12 and 8% H2O2. Despite this, the subcritical water extraction method highlights the potential of a simple process as a technological option to convert underutilized side streams like beer bagasse into added-value, potential ingredients for innovative food and pharmaceutical applications.

A critical review on the biotechnological potential of Brewers' waste: Challenges and future alternatives

In order to comply with the stringent discharge guidelines issued by governmental organizations to protect the ecosystem, the substantial amounts of effluent and sturdy wastes produced by the beer brewing process need to be discarded or handled in the most affordable and secure manner. Huge quantities of waste material released with each brew bestow a significant opportunity for the brewing sector to move towards sustainability. The concept of circular economy and the development of technological advancements in brewery waste processing have spurred interest to valorize brewery waste for implementation in various sectors of medical and food science, industrial science, and many more intriguing fields. Biotechnological methods for valorizing brewery wastes are showing a path towards green chemistry and are feasible and advantageous to environment. The study unfolds most recent prospectus for brewery waste usage and discusses major challenges with brewery waste treatment and valorization and offers suggestions for further work.

Impact of Circular Brewer’s Spent Grain Flour after In Vitro Gastrointestinal Digestion on Human Gut Microbiota

Brewer’s spent grain (BSG) solid residues are constituted by dietary fibre, protein, sugars, and polyphenols, which can have potential effects on human health. In this study, for the first time, the flours obtained from solid residues of solid-liquid extraction (SLE) and ohmic heating extraction (OHE) were applied throughout the gastrointestinal digestion simulation (GID), in order to evaluate their prebiotic potential and in vitro human gut microbiota fermentation. The results showed that the digestion of BSG flours obtained by the different methods lead to an increase throughout the GID of total phenolic compounds (SLE: from 2.27 to 7.20 mg gallic acid/g BSG—60% ethanol:water (v/v); OHE: 2.23 to 8.36 mg gallic acid/g BSG—80% ethanol:water (v/v)) and consequently an increase in antioxidant activity (ABTS—SLE: from 6.26 to 13.07 mg ascorbic acid/g BSG—80% ethanol:water (v/v); OHE: 4.60 to 10.60 mg ascorbic acid/g BSG—80% ethanol:water (v/v)—ORAC—SLE: 3.31 to 14.94 mg Trolox/g BSG—80% ethanol:water (v/v); OHE: from 2.13 to 17.37 mg Trolox/g BSG—60% ethanol:water (v/v)). The main phenolic compounds identified included representative molecules such as vanillic and ferulic acids, vanillin and catechin, among others being identified and quantified in all GID phases. These samples also induced the growth of probiotic bacteria and promoted the positive modulation of beneficial strains (such as Bifidobacterium spp. and Lactobacillus spp.) present in human faeces. Moreover, the fermentation by human faeces microbiota also allowed the production of short chain fatty acids (acetic, propionic, and butyric). Furthermore, previous identified polyphenols were also identified during fecal fermentation. This study demonstrates that BSG flours obtained from the solid residues of SLE and OHE extractions promoted a positive modulation of gut microbiota and related metabolism and antioxidant environment associated to the released phenolic compounds.